rroom
if(!rroom(sdx*d,sdy*d))
if(!rroom(sdx*( (d*adx)/ady ), sdy*d) ||
!rroom(sdx*( (d*adx-1)/ady+1 ), sdy*d))
if(!rroom(sdx*d, sdy*( (d*ady)/adx )) ||
!rroom(sdx*d, sdy*( (d*ady-1)/adx+1 )))
static int rroom(int, int);